European published application No. 34440 describes such a coupling where the coupling elements each comprise two pivoted links carried on cantilevered pins secured in the rigid flanges of the input and output members. A similar tandem arrangement is disclosed in European published application No. 95264. To be sufficiently rigid and strong such an arrangement is found in practice to be very heavy and the flanges account for about 80% of the weight of the coupling.
It is therefore an object of this invention to provide a coupling which is relatively light by comparison with the art but not any weaker or less capable in terms of torque, speed and stiffness characteristics.